First successful test

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graymee
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First successful test

Postby graymee » 14 Aug 2011, 1:42pm

In the past when I've gone touring we've got away with charging our phones wherever we could get mains power or using the cheapy Tevion solar panel we bought in Aldi. This year we're doing a bit of wild camping and my HTC Desire is slightly more power hungry that the Nokia I used last year. I'm fairly confident the solar panel won't be up to charging my phone so I'll use that to charge the wife's Nokia.

On here I've seen various threads suggesting various solutions, most revolving around a hub dynamo and an E-Werk or some similar device however the cost was somewhat prohibitive. Being a tight fisted Jock with a distant background in electronics I decided to build something a lot cheaper and today was the first successful test.

My solution is a 6V 3W bottle dynamo (£13) feeding a home made bridge rectifier and voltage regulator which cost less than £5.

Now I know that lots of people will say that the bottle dynamo will cause a lot more drag than a hub dynamo however, as I'm going to towing a fairly heavily laden trailer, I doubt very much that I'll notice it!

Today I just used it to charge the battery in the solar panel to ensure it was working, tomorrow or Tuesday I'll plug the phone in via the USB cable and see how I get on. So far I'm pretty happy having spent less than £18. The golden solution (SON hub dynamo and E-Werk) would have cost £158 for the dynamo, £153 for the E-Werk and around £14 for spokes to build the dynamo into a wheel,total cost £325. A considerable difference!
I'm not old and cynical, I'm realistic!

snibgo
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Re: First successful test

Postby snibgo » 14 Aug 2011, 2:08pm

As you say, a massive difference. Excellent. From my distant youth building power supplies, I seem to recall using a largish capacitor to smooth the voltage, and maybe a resistor to limit current.

Let us know how it goes.

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al_yrpal
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Re: First successful test

Postby al_yrpal » 14 Aug 2011, 4:15pm

Perhaps better to charge a battery and using that to charge your phone rather than risking your phone direct?

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. CTC gone but not forgotten!

mattraisin
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Re: First successful test

Postby mattraisin » 14 Aug 2011, 4:23pm

For my JOGLE last year many attempts were made to make this work and ended up being unable to. The best we got were false starts where it appeared to be charging a battery pack and then the phone but on long distant rides it was obvious it wasn't. would be good to have circuit diagram to see where we went wrong and to know if you have had a sucessfull test charging of your phone. I recomend running GPS or some form of heavy drainage on your phone to actually see if it works and to do a good 40-60 miles. I never notticed until the longer runs. Bench tests just didnt cut it.
A puncture in the middle of nowhere simply gives you more time to admire the view.

mattraisin
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Re: First successful test

Postby mattraisin » 14 Aug 2011, 4:24pm

oh and I picked up a shimano hub dynamo built into a shimano rim for 50 quid on ebay brand new and it worked without hickup and was decent quality.
A puncture in the middle of nowhere simply gives you more time to admire the view.

graymee
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Re: First successful test

Postby graymee » 14 Aug 2011, 4:43pm

Snibgo, it's slightly more advanced than that. It's got a Maplin W005 bridge rectifier feeding an LM2940 voltage regulator smoothed by a couple of capacitors all mounted in an old puncture repair kit plastic box. The output is fed out via an old USB lead and should be regulated to the 5 +/- 0.25V that you normally get from your computer.

Mattraisin, I require a dynamo with a disk mount (6 bolt), that bumps the cost up although I could possibly fit a centre lock disk hub. That would incur more cost buying another disk rotor. Even if I did get a hub dynamo cheap just the spokes to build the wheel would cost almost as much as I spent in total.
I'm not old and cynical, I'm realistic!

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al_yrpal
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Re: First successful test

Postby al_yrpal » 14 Aug 2011, 5:17pm

graymee wrote:I require a dynamo with a disk mount (6 bolt), that bumps the cost up although I could possibly fit a centre lock disk hub. That would incur more cost buying another disk rotor. Even if I did get a hub dynamo cheap just the spokes to build the wheel would cost almost as much as I spent in total.


I just did that. A 6 bolt Shimano dynamo hub from Rosebikes for £30 http://www.rosebikes.co.uk/article/shim ... aid:196617 and a new pair of 26" wheels with Rigida Grizzly rims from Spa built by 531colin with an XT rear hub and 36 spokes for £156. My motive was partially to upgrade the wheels from the no name Halfords ones on my bike. I am now riding on wheels I trust, and generating current for my phone. Expensive, (IMO), but a good long term investment that can be moved from bike to bike.

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. CTC gone but not forgotten!

rjb
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Re: First successful test

Postby rjb » 14 Aug 2011, 9:52pm

link here to a similar query
viewtopic.php?f=5&t=38265&hilit=+charger
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, 2 Dawes Kingpins, Raleigh 20, Falcon K2 MTB dropped bar tourer, On One Pompino, Longstaff trike conversion on a Falcon corsa. :D

fatboy
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Re: First successful test

Postby fatboy » 15 Aug 2011, 7:54am

al_yrpal wrote:I just did that. A 6 bolt Shimano dynamo hub from Rosebikes for £30 http://www.rosebikes.co.uk/article/shim ... aid:196617


What's the "cheap" dynamo like? I like the idea of a hub dynamo but can't justify a SON or even an expensive Shimano one.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

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al_yrpal
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Re: First successful test

Postby al_yrpal » 15 Aug 2011, 9:53am

fatboy wrote:
al_yrpal wrote:I just did that. A 6 bolt Shimano dynamo hub from Rosebikes for £30 http://www.rosebikes.co.uk/article/shim ... aid:196617


What's the "cheap" dynamo like? I like the idea of a hub dynamo but can't justify a SON or even an expensive Shimano one.


Well made and beautifully finished, seems fine. Quite a bit of resistance if you try and spin the spindle with your fingers, but when its in the wheel its practically unoticable. As for the hub bearings I dont know how they compare with an XT, but Shimano name is prominent.

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. CTC gone but not forgotten!

graymee
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Re: First successful test

Postby graymee » 20 Aug 2011, 7:13pm

Having shown that my bottle dynamo and associated circuitry will charge the battery in my solar panel I eventually got round to trying to charge my phone. After my short test ride I notice that the phone battery level hadn't increased so carried out a bit of fault diagnosis, found that the input and output cables weren't adequately secured and that one of the output connections had come off the circuit board. The whole lot is now in my kitchen so I can solder the connections back on and secure the cables so they don't pull out again.
I'm not old and cynical, I'm realistic!

snibgo
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Re: First successful test

Postby snibgo » 20 Aug 2011, 9:22pm

Great stuff. When it is debugged, you might use potting compound to resist water and vibration, but you'll need to let the regulator cool. (Sorry, I'm probably teaching my grandmother how to suck eggs.)

freebooter
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Re: First successful test

Postby freebooter » 21 Aug 2011, 11:08am

Nokia sell a bottle dynamo charger. I haven't tried it myself but it may provide an easier solution for those who don't fancy the diy approach and is much cheaper than the hub dynamo ones.

http://www.nokia.co.uk/find-products/ac ... harger-kit